The First INTEGRAL SPI-ACS Gamma-Ray Burst (GRB) Catalog contains the sample of gamma-ray bursts detected with the Anti-Coincidence Shield (ACS) of the SPI spectrometer on-board the INTEGRAL spacecraft for the first 26.5 months of mission operations (up to January 2005). The SPI-ACS works as a nearly omnidirectional gamma-ray burst detector above ~80 keV, but it lacks spatial and spectral information. In this catalog, the properties derived from the 50 millisecond (ms) light curves (e.g., T_90, C_max, C_int, variability, and V/V_max) are given for each candidate burst in the sample. A strong excess of very short events with durations < 0.25 seconds is found. This population is shown to be significantly different from the short- and long-duration burst sample by means of the intensity distribution and the V/V_max test and is certainly connected with cosmic ray hits in the detector. A rate of 0.3 true gamma-ray bursts per day is observed. This table lists the properties of 388 GRB candidates detected from Oct 27, 2002 to Jan 15, 2005 with the Anti-Coincidence Shield (ACS) of SPI. It has numerous events with missing entries, notice. For all GRBs which were confirmed by other instruments but were detected by SPI-ACS below the sample selection threshold, only the time, date, significance and common instruments are listed. Furthermore, the variability measure was obtained only for long-duration events which had sufficiently large signal-to-noise ratios. This table was created by the HEASARC in October 2005 based on CDS table J/A+A/438/1175/table2.dat . This is a service provided by NASA HEASARC .